Any vector in ${\mathbb R}^3$ perpendicular to $$\left[\begin{array}{c} -6\cr 2\cr -7 \end{array}\right]$$ can be written in the form
$\left[\Rule{0pt}{3.6em}{0pt}\right.$$\left]\Rule{0pt}{3.6em}{0pt}\right.$ $s +$ $\left[\Rule{0pt}{3.6em}{0pt}\right.$$\left]\Rule{0pt}{3.6em}{0pt}\right.$ $t.$